This invention relates to a method for manufacturing multi-layer hemodialyzers, which is particularly adapted for mass production techniques. For another of its aspects, the invention also concerns an improved multi-layer hemodialyzer structure.
There are to be found described in the specialized literature multi-layered hemodialyzers which comprise parallel-arranged tubular semi-permeable membranes and supporting members having various surface configurations which are interposed between such membranes. The membranes define interiorly a chamber for blood, or alternatively a dialyzing liquid, to pass therethrough, while the spaces left between the membranes and said supports define a passage area, respectively for the dialyzing liquid or blood. Since the concentration of various impurities in blood is higher than the concentration of those same impurities in the dialyzing liquid, a concentration gradient is created through the semi-permeable membrane which induces, by a dialysis process, transfer of impurities from blood into the dialyzing liquid, to achieve thereby purification of the blood.
Also described are multi-layered hemodialyzers of the type mentioned above, wherein the blood passage area is sealed from the dialyzing liquid passage area by means of a resin layer, in particular epoxy resin, provided around the ends of said tubular membranes so as to leave those ends open and to close the spaces between the open ends of each tubular membrance and the open ends of respective overlying or underlying membranes.
The multi-layer hemodialyzers of the type mentioned above, while being highly effective, never met with widespread commercial acceptance owing to the lack of any suitable mass manufacturing method. Actually, the methods proposed heretofore for producing multi-layer hemodialyzers are very complex, involve several operations requiring the manual intervention of an operator, and thus they are unsuitable for mass production techniques.
In addition thereto, the multi-layer dialyzer designs currently in use have some disadvantages, such as blood purification effectiveness, which is not always entirely satisfactory.